Without limiting the scope of the invention, its background is described in connection with methods and compositions for diagnosis and treatment of prostate cancer.
Prostate cancer is the second most common cancer in older men, after skin cancer. Despite major efforts in the last 20 years to improve detection and therapies, prostate cancer is still a leading cause of morbidity and death in men throughout the world, e.g., 192,280 new prostate cancer diagnoses with 27,360 related deaths are estimated in the United States and even higher in the European Union with 301,500 new cases and 67,800 deaths expected every year (1). Unlike 20 years ago when more than 50% of men newly diagnosed with prostate cancer displayed metastases, today the majority are confined to the prostate gland (2). Such diagnostic improvement was due to the development of new screening techniques for earlier prostate cancer detection based on tumor biomarkers.
Prostate specific antigen (PSA) is the best known prostate cancer biomarker, introduced in 1986 (3) and FDA-approved in 1994 (4). However, growing evidence indicates that PSA testing is less than ideal as a screening technique for prostate cancer detection, since it suffers from high false positive and false negative rates, causing healthy men to undergo unnecessary prostate biopsies in 75% of cases (5), and about 27% of cancer-bearing men to be misdiagnosed (6).
Prostate cancer is difficult to diagnose because the prostate specific antigen screening method is associated with many false positives. In addition there is a need to develop new and more effective treatments. Among presently available new treatments, immunotherapy is a promising approach. The expression of the cancer/testis antigen, AKAP-4, was tested in prostate cancer patients to evaluate the possibility of exploiting AKAP-4 as a target for immunotherapy.